David Cameron prepares for 'hard bargaining' ahead of EU summit

For David Cameron, today is Summit Eve.

It's a bit like Christmas Eve - with the noteable difference that there isn't much to look forward to the next day.

Because tomorrow, over dinner in Brussels, the prime minister will meet the other 27 European leaders and attempt to make some progress on his big EU renegotiation plan.

Mr Cameron has outlined four areas in which he wants reforms in Britain's membership before putting the deal to the British people in his referendum before the end of 2017.

The first three areas are relatively straightforward: an end to the binding principle of 'ever closer union'; greater competitiveness and less red tape; and protection for those countries which do not use the Euro.

But the sticking point is his proposal to ban EU workers from access to in-work benefits and social housing for four years.

There has been scarcely any progress on this demand.

Most of his counterparts consider it to be a threat to some of the founding principles of the entire European project: the free movement of workers between members states; and prohibiting discrimination between the citizens of different EU countries.

And today the German Chancellor Angela Merkel, the most powerful voice in the EU, told David Cameron she will not compromise on those principles.

'They are not up for negotiation', she told German MPs in the Bundestag as they applauded her.

It will make for some hard bargaining around the table in Brussels tomorrow.

Ms Merkel did say Britain was a 'natural ally', that the UK contributes to the EU's economic growth, that our place as a permanent member of the United Nations Security Council 'contributes significantly to the European Union's importance in the world.'

And the German leader even said she wanted a deal where, in the referendum, the 'British people will successfully decide to stay in the EU.'

Warm words, but unless tomorrow she suddenly agrees to the British benefit ban - and also persuades the majority of other European leaders to do so too, it's hard to see how David Cameron can make any progress at all.

The European Council President Donald Tusk has already urged all sides to make compromises.

But given many of his MPs back here think Mr Cameron is only asking for 'thin gruel' in the first place, compromise on this issue will make for a difficult few weeks ahead of the final agreement, scheduled for a summit February.

On Summit Eve in the Cameron house, they won't be waiting in too much anticipation for the next day's big dinner.